PGM-Free Oxygen-Reduction Catalyst Development for Proton-Exchange Membrane Fuel Cells:Challenges,Solutions,and Promises

作     者：Yanghua He Gang Wu 

作者机构：Department of Chemical and Biological EngineeringUniversity at BuffaloThe State University of New YorkBuffaloNew York 14260United States 

出 版 物：《Accounts of Materials Research》 (材料研究述评（英文）)

年 卷 期：2022年第3卷第2期

页      面：224-236页

学科分类：081704[工学-应用化学] 07[理学] 070304[理学-物理化学(含∶化学物理)] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 

基　　金：We acknowledge the financial support from the U.S.Department of Energy,Office of Energy Efficiency and Renewable Energy(EERE) Hydrogen and Fuel Cell Technologies Office(DE-EE0008075,DE-EE0008076,and DE-EE0008417) National Science Foundation(CBET-1604392,1804326) 

主　　题：catalyst Oxygen durability 

摘      要：CONSPECTUS:Proton-exchange membrane fuel cells(PEMFCs)are efficient and clean hydrogen energy technologies for transportation and stationary *** active and durable low-cost cathode catalysts for the oxygen-reduction reaction(ORR)under challenging acidic environments are desperately needed to address the cost and durability issues of *** most promising platinum group metal(PGM)-free catalysts for the ORR in acidic media are atomically dispersed and nitrogencoordinated metal site catalysts denoted as M−N−C,M=Fe,Co,or *** to significant efforts in the past few decades,these catalysts have demonstrated much-improved ORR activity and promising initial fuel cell performance approaching traditional Pt/C ***,the insufficient long-term stability(up to 5000 h)under PEMFC operation represents a primary technical barrier to making current PGM-free catalysts less viable yet in *** this Account,we highlight recent advances in synthesizing efficient PGM-free catalysts for the ORR in PEMFCs,emphasizing effective strategies to improve mass and intrinsic activity and the possible degradation *** particular,a chemical doping method based on the zeolitic imidazolate framework(ZIF)-8 represents the key to developing efficient M−N−C catalysts containing atomically dispersed and nitrogen-coordinated single metal active sites(i.e.,MN_(4)).The newly acquired understanding of the formation mechanism of MN_(4)active sites during the thermal activation and its correlation to catalytic properties guide the rational catalyst design rather than relying on current trial-and-error *** efforts have further been invested in increasing the active site density and enhancing intrinsic activity by regulating carbon-phase structures and the local coordination *** highly active catalysts usually suffer from significant activity loss during the ***,breaking the activity−stability trade-off is the key to simul